Exemplary embodiments of the present disclosure relate to a bucket mounted on a rotor wheel of a turbine, and more particularly, to a fixture for a bucket for a turbine blade and an assembling method of a bucket using the same for easy installation of a plurality of buckets installed along a circumferential direction of a rotor wheel.
Generally, a steam turbine is an apparatus for rotating buckets with blades with high temperature and high pressure steam generated from a large-capacity boiler for a power station to convert into rotary power which is kinetic energy and is generally divided into a high pressure turbine, an intermediate pressure turbine, and a low pressure turbine to maximize efficiency.
The steam turbine includes a casing forming an appearance and a frame of the turbine and a rotor rotatably installed in the casing.
Each bucket includes a blade part and a root part, in which the root part includes a platform that is formed at a radial internal end of the blade part and a dovetail that is formed at a radial internal end of the platform.
Generally, the foregoing dovetail may be largely divided into a tangential entry type, an axial entry type, a pinned finger type, and a key axial shape according to a method for coupling a dovetail with a rotor.
In the case of the axial entry type bucket in which the bucket is inserted into and fastened with the dovetail in an axial direction of the rotor, the bucket is fixed in a tangential direction of the rotor by the dovetail but is not fixed in an axial direction of the rotor, and therefore there is a problem in that the bucket is separated during a driving of the turbine.
To solve the above problem, the axial entry type used the axial fixture for the bucket. However, in the existing axial entry type, the axial fixture of the bucket has a complicated configuration, and therefore there is a problem in that it takes much time and costs to perform the axial fixing.
Further, in the existing axial entry type, the axial fixture has a complicated configuration, and therefore there is a problem in that manufacturing costs are increased.
In addition, in the existing axial entry type, the axial fixture of the bucket may not firmly fix the bucket in the axial direction and in severe cases, the bucket is separated from the rotor due to vibrations depending on the driving of the turbine, and therefore there is a problem in that a safety accident is caused.